The aim of this study is to establish if the San Luis Potosi Plateau (SLPP), which is part of the southern edge of the Chihuahuan Desert, is generating desertification processes, indicating a progression of the desert toward the central part of Mexico. Therefore, we analyzed the temporal evolution of four environmental indicators of desertification: Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), Iron Oxides Index (IO) and Surface Temperature (ST). Landsat TM images are used to cover a period from 1990 to 2011. A new equation of total balance is proposed to generate an image of the overall evolution of each factor which is applied to get a probability map of desertification. The evolution of NDVI, NDWI and IO shows a behavior almost stable over the time. In contrast, the ST shows a slight increase. The outcomes of this study confirm periods of vegetation re-greening and 8.80% of the SLPP has the highest probability to develop desertification. The most affected area is the portion west of the region, and the east and south are the least affected areas. The results suggest a slight advance of the desert, although most of the area doesn't have the necessary conditions to develop desertification.

El jitomate es la principal hortaliza de mayor importancia económica a nivel internacional y nacional, cuya producción es limitada cuando se establece en suelos salino-sódicos e irrigado con agua salina, condiciones abióticas presentes en regiones áridas y semiáridas de México. El objetivo fue evaluar el efecto del azufre elemental (S◦ ) y la gallinaza en los índices morfológicos, producción de biomasa y rendimiento en jitomate, cultivado en un suelo suelo salino-sódico e irrigado con agua salina. El hibrido de jitomate saladette Conan USATX 2112, se estableció en invernadero tipo malla sombra en Moctezuma San Luis Potosí, en suelo salino-sódico; se utilizó un diseño de tratamientos factorial 2x4, con dos dosis de azufre, 750 (S1) y 1 500 kg ha−1 (S2) y cuatro dosis de gallinaza (1, 2, 3 y 4 t ha−1 ). En planta se realizaron cinco muestreos no destructivos a los 14, 24, 30, 45, 69 días después del trasplante (DDT) estimándose los componentes morfológicos. De igual forma a los 54, 63 y 83 DDT se realizaron muestreos destructivos evaluándose la materia fresca y seca total, y su distribución por estructura de la planta, peso y rendimiento de fruto. Los componentes morfológicos fueron afectados positiva y significativamente por la adición de 750 kg ha−1 (S1), con respecto al tratamiento de 1 500 kg ha−1 (S2). En el tratamiento S1 tuvo mayor porcentaje de MS en fruto (35%), mientras que S2 sólo un 18%. Las dosis de gallinaza no presentaron diferencias significativas en ninguna variable evaluada.

Objective: The most appropriate conditions for genetic transformation through direct (bioballistic) and indirect (Agrobacterium tumefaciens) transformation systems in Paulownia elongata were established. Design/methodology/approach: Starting from in vitro propagation through both direct and indirect organogenesis, internodal stem segments with 0.5 to 1 cm length were determined as the best explant. The optimum dose for selection media was determined to be 15 mg L-1 of kanamycin. It was possible to obtain transgenic plants under both transformation systems. In the case of Agrobacterium tumefaciens, two hours of incubation, 48 h of co-cultivation, and optical density of 0.9 were used; while for bioballistics, the best conditions were 120 PSI of shot pressure, shot height at level 6 (16 cm), and vacuum pressure of 22 Hg mm, with particle inflow gun system (PIG). Results: Both systems produced complete transformants, chimeras, as well as those confirmed by histochemical X-GLUC and PCR analysis, producing a total of 14 positive plants by A. tumefaciens transformation from 26 trials and ten positive plants by the bioballistic system from 30 trials; a construction with chitinase and glucanase, NPT II selection gene and the GUS reporter gene were used. Findings/conclusions: So far, this has been the first report including integration of chitinase and glucanase genes.